Wide phase boundary zone, piezoelectric properties, and stability in 0.97(K0.4Na0.6)-(Nb1-xSbx)O-3-0.03Bi(0.5)Li(0.5)ZrO(3) lead-free ceramics

In this work, the rhombohedral (R) and tetragonal (T) phase boundary of the 0.97(K0.4Na0.6)(Nb1-xSbx) O-3-0.03Bi(0.5)Li(0.5)ZrO(3) piezoceramics has been attained in a wide composition range of 0.035 <= x <= 0.08, and the Sb5+ could simultaneously shrink its TR-O and TO-T. A giant d(33) of 380-405 pC N-1 and a T-C of 200-292 degrees C have been observed in the ceramics with the coexistence of both R and T phases. In addition, the ceramics with 0.035 <= x <= 0.08 also show a good thermal stability of the d(33), and an enhanced temperature stability of ferroelectricity could be observed in the ceramic with x = 0.035. As a result, adding the optimum antimony content is an efficient way to promote the electrical properties of potassium-sodium niobate ceramics with the R-T phase boundary.